Automobile engines have been fueled by various means over the years. Carburetors were initially used with success for many years. As emissions standards and fuel mileage became more of a concern, fuel injection systems began to appear on engines. For example, throttle body injection was an improvement over the carburetor in that it was able to use closed-loop technology to more accurately fuel the engine over a wider range of operating conditions. A throttle body injection system, however, utilized a single point of injection, usually within a throttle body. As such, throttle body systems still had less than optimum fuel mixing and distribution characteristics. Multi-point fuel injection systems overcame this by providing an injector for each cylinder of the engine. Generally, each fuel injector is received in an injection port located either in an intake manifold runner or in the cylinder head. The injector is connected to a fuel supply such as a fuel rail. An engine control module typically sends a pulse width modulated (PWM) signal to the injector to control the injector's fuel flow.
Conventional fuel injectors are generally fixed with respect to the maximum amount of fuel that can be delivered from any one fuel injector to the combustion chamber. This amount can be insufficient to satisfy the fuel demand for particular constructional forms of the engine. For example, performance modifications or conversion to a different fuel such as methanol may require a greater mass of fuel than the original injector can supply. The conventional solution to this problem has been the use of multiple fuel injectors along with the corresponding multiplicity of flow paths, connectors, seals and computer controlled fuel injector drivers per combustion chamber of the engine. The use of multiple injectors can increase cost and can reduce reliability of a fuel delivery configuration overall.
Another drawback of conventional fuel injectors can be that as the amount of fuel a fuel injector delivers increases, the size of the fuel injector correspondingly increases. Increased size of the fuel injector can increase the distance between the fuel rail and the manifold resulting in a fuel delivery configuration which cannot be used or can be impractical to use as to certain applications, as it may interfere with other engine equipment or the vehicle's hood, for example.